Primary cardiac tumours are rare in the paediatric age group. Bronchogenic cysts, although relatively rare, represent the most common cystic lesion of the mediastinum. Intracardiac bronchogenic cysts however, are extremely rare. The authors are unaware of any case previously reported in a Nigerian child and hence report the case of a 2-year-old boy for its rarity and interest. The boy was referred for evaluation of a cardiac murmur. Clinical, radiological and electrographic findings were suggestive of mild pulmonary stenosis or an atrial septal defect (ASD). 2-dimensional echocardiography however, revealed in addition to a small ASD, an intracardiac mass attached to the tricuspid valve. The mass was surgically removed and found on histology to be a bronchogenic cyst. Our experience highlights the importance of echocardiography in the evaluation of asymptomatic patients with cardiac murmurs, in whom a rare lesion might have otherwise been missed.